Weather drivers in Western Australia 2009-02-04T00:06:07Z 2009-02-05T21:45:06Z Weather drivers in Western Australia Communicating Climate Change - Module 1 <p>The driving force behind our weather is the general circulation of the atmosphere, caused by unequal heating of the Earth's surface. Energy from the sun causes uneven heating of land and sea surfaces near the equator and evaporation from tropical oceans.</p> <p>An extensive area of high pressure, known as the <strong>sub-tropical ridge</strong>, is a major feature of the general circulation of our atmosphere. This belt of high pressure encircles the globe at the middle latitudes. The position of the ridge varies with the seasons, allowing cold fronts to pass over southern Western Australia in the winter, but pushing them to the south in summer. Conditions along the ridge tend to be stable and dry because of descending air in the high-pressure systems.</p> <p>Australia&rsquo;s climate varies across many different regions and timescales. Here we introduce the major elements that affect the weather and climate of Western Australia, and in particular south-west Western Australia.</p> PN22168 PN22168